[DNA level in the cell nuclei of rectal mucosa and rectal cancer during preoperative radiotherapy].

A microspectrophotometric study was made of DNA in cell nuclei of the normal mucous membrane and rectal tumors in 47 patients prior to and after irradiation at doses of 20, 40 and 36 Gy together with the administration of 7 g of 5-fU. The work was done using biopsies (before the onset of therapy) and operative material. As to Felgen-DNA in cell nuclei the normal mucous membrane has been shown to consist of homogeneous cell population with diploid nuclei. Rectal adenocarcinoma is characterized by polyploidy, an increase in the "DNA accumulation index" that grows with a decrease in the degree of tumor differentiation. A slightly raised "DNA accumulation index" is noted in the unchanged rectal mucosa after radio- and chemotherapy, signs of noticeable poly- and heteroploidy of the nuclei of the preserved cells were established in adenocarcinomas.